Papermaker&#39;s felt, woven fabrics and fibers of wool modified with an aldehyde - 4,4 - bis(4 - hydroxy phenyl) pentanoic acid reaction product and the production thereof



United States Patent PAPERMAKERS FELT, WUVEN FABRICS AND FI- BERS 0F WQOL MODIFIED WITH AN ALDE- HYDE 4,4 BIS(4 HYDROXY PHENYL) PENTA- NOIC ACID REACTION PRQDUQT AND THE PRODUCTHON THEREOF Arthur E. Manasian, Newfane, and George Lehner, Rensselaer, N.Y., assignors to Huyck Corporation, Stamford, Conn., a corporation of New York No Drawing. Filed Oct. 1, 1962, Ser. No. 227,540

17 Claims. (Cl. 8127.6)

This invention relates to a process for treating protein materials and to the product resulting therefrom, and more particularly relates to the process and product of treating wool.

Protein materials consist of protein molecules made up of various amino acids linked through amido linkages to form long chain structures called polypeptides. Individual properties of proteinaceous materials are caused by variations in the proportion and arrangement of the different amino acids. Other factors affecting properties are variations in chain lengths, degree of cross-linking and the presence of other groups in linkages other than the basic peptide linkages. In many cases protein fibers are deficient in their tensile properties because there are insufficient cross-linkages between the peptide chains or because the linkages present in the dry fiber are easily broken.

Wool and other protein material can be modified to advantage using precondensates of polyhydric phenols and formaldehyde. Also, protein materials, particularly leather, can be modified with water soluble or solvent soluble condensation products of phenols and aldehydes. DihydroXy and trihydroxy derivatives of benzene and their substitution products can be used effectively with aldehydes to modify proteinaceous materials. Monohydric phenols having sufficient reactivity will combine with formaldehyde and wool resulting in a weight increase and possibly some change in properties. However, the known reactants which produce the desired improvements in properties also have the undesirable result of adversely affecting the color of the treated protein material. The color may be imparted to the material when heated or may arise after use or upon exposure to heat or light.

This invention is useful as a shrinkproofing and wash and wear treatment for woolen clothing and other fabrics.

The invention may also be used as a modifier of felt hats and as a leather tanning agent. The known processes using phenolic resins for shrink-proofing or applying wash and wear treatment to woolen clothing and other fabrics result in an undesirable discoloration of the material treated. The present invention treats such materials without causing discoloration.

The present invention is particularly applicable to papermarkers felts. A papermarkers felt is a woven fabric, usually wool, which is usually fulled after weaving to form a firm fabric of specific desired dimensions. Having been fulled to predetermined dimensions, it is essential to the successful use of the felt that it maintain these dimensions as closely as possible. Such felts are employed to convey wet paper from a web forming device to and through apparatus used in the paper making process. The felt is subject to much abrasion and chemical action in use and has a relatively short life. It is essential that the felt have high tensile strength because it is subject to much ICC stress and stretching in the paper making apparatus. The felt must have a high degree of porosity to allow water to drain freely through the felt as it passes through the various paper making steps. The felt must be easily cleanable because the felts tend to fill up with foreign matter and small fibers of pulp which must be regularly removed. Satisfactory drainage of water from the wet pulp must be maintained so that the speed of the paper making process is not reduced because of insufficient water removal from the wet pulp. To meet all of these requirements the wool fibers used in papermakers felts must be chosen without regard to cost. Thus the life of the felt is a substantial factor in the cost of producing paper and other articles made from wet pulp.

Small particles breaking off of the felt will frequently find their way into the resultant paper product. If the felt is colored such particles will be readily apparent in or on a white paper; hence, it is desirable that the felt be white or light cream colored. The various phenolic treatments which are used to increase the physical and chemical properties of papermakers felt have the undesirable side effect of discoloring the felt.

It is an object of this invention to provide a process for improving the physical and chemical properties of proteinaceous material.

It is a further object of this invention to provide a process of treatment which modifies proteinaceous material to impart increased dimensional stability, wear-resistance, bacterial resistance, chemical resistance, and the like, without modifying the natural color of the material.

It is another object of this invention to provide a proteinaceous product which has improved physical and chemical properties including stretch resistance, wear-resistance, bacterial resistance, chemical resistance and the like.

It is still another object of this invention to provide a wool product which has improved physical and chemical properties yet retains the original wool color when made or used under usual use conditions.

Other objects will be apparent to those skilled in the art from reading the following description.

The objects of this invention are achieved by treating a proteinaceous material with 4,4-bis(4-hydroXy-phenyl) pentanoic acid, which is also known as diphenolic acid, and an aldehyde. Formaldehyde is the preferred aldehyde, but acetaldehyde, or benzaldehyde, or propionaldehyde may be substituted for formaldehyde. The diphenolic acid has a structural formula as follows:

(II-Ia I CH2 hyde reaction is capable of producing significant improvements of an unexpected degree in protein material. Most surprisingly, diphenolic acid and formaldehyde are capable of producing the improvements without adversely affecting the color of the material. The latter advantage is particularly unexpected because the products formed by condensing phenol and formaldehyde with protein are expected by those skilled in the art to be colored. It has been found that there is an increase in weight of the protein fiber which is not readily removable by extraction by solvents in which diphenolic acid-formaldehyde condensates prepared under the mild conditions used are normally soluble. It has also been found that a portion of the amino acids of the protein material is modified during treatment.

Without wishing to be bound by a theory of operation it is believed that a reaction occurs between the protein material and either the diphenolic acid and the formaldehyde or their reaction product. It has been found that the protein material is modified when the reactants are employed simultaneously and in their free and uncombined state. The desirable improvements in the protein material are not obtained if the diphenolic acid and formaldehyde are afforded time to react substantially or to any significant degree with each other prior to the addition of the protein material.

This invention relates primarily to the treatment of protein fibers to cause chemical modifications so that in an atmosphere of high humidity the treated protein fiber behaves more like a dry fiber. When completely saturated with water the treated fiber has increased resistance to extension (stretching).

A fabric made from treated fibers has significantly increased wear resistance as measured by conventional laboratory testers or by practical use. Treated fibers, such as wool, also have improved resistance to size increase under applied stress and improved resistance to size decrease caused by felting. The microbiological resistance of treated fabric is greater than that of untreated fabric.

The process of this invention may be carried out by immersing the protein fiber to be treated in a solution of diphenolic acid and formaldehyde which have not had time to polymerize substantially. The treatment is not effective if the reactants polymerize prior to contacting the protein. After removal from the solution the treated fiber is rinsed with warm Water and dried.

It is preferred to carry out the treatment in an aqueous solution of alcohol, although water alone may be used. Limitations are imposed by use of water alone because diphenolic acid is readily water soluble only at temperatures above about 85 C. In solutions of water and alcohol having low ratios of water to alcohol concentration, the reaction proceeds at a slow rate. Without wishing to be bound by a theory of operation, it is believed that the slow rate is due to the fact that the fibers do not swell sufiiciently unless sufiicient water is present. Good results are obtained when alcohol concentration is less than 30% by volume. The process may be used with any solvents which cause the fibers to swell. Any alcohol that is liquid under normal conditions is satisfactory for use; however, methanol, ethanol and isopropanol are perferred alcohols.

The temperature range of the process is determined by the solubility of the diphenolic acid in the solvent system used. The process may thus be conducted within a wide range of temperatures, such as from 50 to 100 C. In treating wool, however, we prefer to carry out the reaction at temperatures between about 60 C. and 100 C.

After an improvement of about 20% in the Work Index, as defined below, has occurred, additional reaction time will not significantly change the properties of the modified product. Treatment with the solution of diphenolic acid and formaldehyde for more than about an hour does not effect significant improvement in properties. It has been found that treatment for about one hour at about 75 C. yields the best results.

The pH of solution may be varied widely, such as from about 2 to 9. If the pH is below about 2, the proteinaceous fibers tend to decompose. If the pH is above about 9, improvement in fiber properties is negligible. Above a pH of about 10, fibers also tend to decompose under conditions of the treatment. A pH between 4.5 and 7.0 has been found particularly satisfactory. The preferred pH range is from 5.5 to 6.5. In practice, a pH of about 5.5 results from the use of diphenolic acid without an added buffer.

Wide ranges of reactant concentrations and reactant ratios may be used. The preferred limits of diphenolic acid concentrations are between about 0.02 and 0.08 mole per liter (M). It has been found that above a concentration of about 0.08 M, little improvement in the properties of treated materials is observed, although their weight continues to increase.

The molar ratio of formaldehyde to diphenolic acid has been varied from 1:2 to 4:1. Higher concentrations of formaldehyde tend to produce a tensilely weaker product than low concentrations. In practice, it is preferred to use a formaldehyde to diphenolic acid molar ratio of about 2:1.

The treating solution to protein ratios may be varied from 0.6:1 to 50:1. However, it is preferred that the ratio be maintained between about 8:1 to 40:1. Best results have been obtained within a solution to protein ratio of about 16 to 1.

It has been found that high temperature curing is not necessary. The reactions are complete when the fabric leaves the reaction mixture. However, temperatures up to C. may be used to speed drying.

The treated product is heavier than the starting protein material. The resulting weight increase rises as the availability and concentration of diphenolic acid increase. The maximum effective weight increase is about 20% at a diphenolic acid molar concentration of 0.08 M using a 16:1 solution to protein ratio. Weight increases beyond about 20% do not result in an improvement in properties.

The process may be used to modify a mixture of protein fibers or a mixture of protein and non-protein fibers. Because the reaction rnodifies only the protein fibers, the treatment may be employed on fabric containing synthetic and other natural fibers without regard to the percentage of protein fiber in the fabric. If however, the fabric contains fibers, such as nylon, which react with one or more of the reactants, due consideration must be given to such reaction in order that a proper level of modification of the protein fiber is reached. Fabrics containing at least 25% proteinaceous material, preferably wool, and up to 75% of a synthetic, such as nylon or Dacron (polyester), by weight, have been treated with no evidence of a limit having been reached, while observing the foregoing cautions. Fabrics, such as for papermakers felts, containing at least about 25 wool, provide a suitable capability of fulling and felting and, when treated in accordance with the invention, have enhanced resistance to wear, microbiological attack, and other enhanced properties over those of the untreated fabric. Those fabrics containing at least about 40% wool are particularly enhanced in their properties by the treatment of the invention.

While nylon will react with one or more of the diphenolic acid or aldehyde reactants, and therefore sufficient amounts of reactants are desirably employed to react with it; other synthetics, such as Dacron, react only slightly, if at all, and when employing such synthetics, little or none of the reactants are needed to react with the synthetic component of the substrate.

The nature of the improvements made possible by the process of the invention and the resultant product is indicated in Tables I-VII below. Table I shows the modifications produced in wool by varying the concentration of the diphenolic acid, the formaldehyde to diphenolic acid molar ratio being held constant at 2:1.

W001 was used as the protein fiber at a treatment solution to wool ratio of 16:1. In preparing the reactants, the diphenolic acid was dissolved in an aqueous solution of 5% by solution volume of isopropanol. The treatment of the wool in the solution of diphenolic acid and formaldehyde was carried out for one hour at 74 C.; after which the wool was rinsed and dried for one hour at 105 C.

The Percent Pickup corresponds to the weight increase of wool during treatment and was determined by comparing the dry weight of the treated product with the dry untreated wool used.

The Pounds Tensile is the breaking strength of the material and was determined by placing a one inch wide strip of material in a standard tensile tester and recording the break point.

The Work Index is a comparison of the force required to stretch treated wool fabrics with the force required to stretch the same fibers prior to treatment. The force required to elongate by 20% a single fiber of material, before and after treatment, is graphed. Force is charted as the ordinate; elongation is charted as the abscissa. The areas under the two resultant curves are compared to determine the Work Index.

The Standard is untreated wool similar in all other respects to the treated wool.

TABLE I Molarity of Molarity of Percent Pounds Diphenolic Formal- Pickup Work Index Tensile acid dehyde Standard- 100 107 .025 .050 5. 4 106.8 89. 7 7.0 110.6 88. 9 8. 3 111. 6 93. 5 10. 2 114. 5 90. 7 11.8 117.4 89. 8 12.3 120.1 91. 6 14. 4 118 91. 6 100 114. 3 15. 4 124 98.8 16. 9 123 97. 6 17. 5 p 129 95. 6 18. 4 121 97. 9 10. 5 122 102. 21. 4 125 106. 22. 1 125 103. l 23. 3 129 102.3 24. 5 123 I09. 1 25.7 128 104. 7

Table I shows that above a diphenolic acid concentration of 0.060.07 M, the increase in weight of the protein fiber does not result in any further improvement in fiber properties as indicated by the Work Index.

Table I also shows that the percent of weight pickup increases as the rnolarity of the diphenolic acid increases. Thus, the increase in Percent Pickup is directly proportional to the amount of diphenolic acid that is available for reaction.

Table II below, shows the results of using a formaldehyde to diphenolic acid ratio of 1:2. The procedures were otherwise the same as used in the tests set forth in Table I.

The Percent Pickup in Table II varies directly as the amount of diphenolic acid available for reaction. The

increase in weight reflects an increase in fiber modification as indicated by the Work Index. The maximum fiber modification is reached at a diphenolic acid molarity of about 0.075. The use of a formaldehyde to diphenolic acid molar ratio of 1:2 has practically no effect, within the limits of experimental accuracy, on the tensile strength as indicated under Pounds Tensile. As shown in Table I the use of a formaldehyde to diphenolic acid ratio of 2:1 resulted in reduced tensile strength.

It may be concluded from Table II that the reduction of concentration of formaldehyde did not significantly change any of the resultant properties, except that an improved tensile strength was obtained.

Table III below, shows the effect of a 4:1 formaldehyde to diphenolic acid molar ratio. The solutions used in the preparation of the data of Table III were made by dissolving the diphenolic acid in 50 ml. of isopropanol with rapid stirring at room temperature. The resulting solution was added to 950 ml. of water preheated to 70 C. to make a treating solution of the desired molarity. Wool felts were added to the solution; the formaldehyde was then added, and the reaction was continued with agitation for one hour. The felts were then removed, washed with cold tap water and dried for one hour at C. The solution to wool ratio used was 16 to 1; the pH of the solution was 5.5.

TABLE III Molarlty of Molarity of Percent Pounds Diphenolic Formal- Pickup Work Index Tensile acid dehyde Standard. 107 .025 I. 100 5. 6 107. 9 84. 1 12 7.0 110.1 89. 7 8. 5 115. 1 88.8 .16 10. 4 113. 2 86.0 10.5 114.2 83. 3 .20 11.0 124.0 89. 7 22 12. 7 123. 0 89. 0

It may be concluded from the data presented in Table III that the Percent Pickup varies directly as the amount of diphenolic acid that is available for reaction. It may be further concluded that the Work Index reaches a maximum at a diphenolic acid molarity of about 0.05. It may be further concluded from Table III that a high ratio of formaldehyde to diphenolic acid results in a reduction in tensile strength as indicated in the Pounds Tensile column.

The data of Table IV, below, is based on the same tests as those of Table I, above, except that the reaction time was increased from one hour to one and one-half hours. It may be concluded from the data of Table IV, (1) that the reaction is complete in about one hour, and, (2) that increasing the reaction time to more than about one hour does not further improve protein properties.

TABLE IV Molarity of Molarity of Percent Pounds Diphenolic Formal- Pickup Work Index Tensile acid dehyde Table V below, illustrates the effect of reactant concentrations on Pickup and Work Index. The effect of reactant concentration was determined by immersing wool samples for one hour in solutions of different molarities of diphenolic acid and different solution to wool ratios. A formaldehyde to diphenolic acid ratio of 2:1 was used in all cases. After immersion the wool samples were rinsed and dried at 105 C.

7" 8 TABLE V The color stability upon aging was determined by exposing treated and untreated samples to sunlight dur- Solution Percent Pickup Work Index ing the summer period. The results are recorded in Table to Protein VII Ratio 0.02M 0.04M 0.06M 0.02M 0.04M 0.06 M 5 TABLE VII 2: 1 2. 2 2. 7 106 105 Time Untreated Treated 4: 1 1. 5 3. 2 5. 103 107 117 8: 1 2. 6.2 9. 7 107 113 114 7 16:1 4.0 10.2 15.4 105 115 1241 g\ U1tr3,.Vi()1etLight; 32:1 6.43 13.2 108 119 v. 21 h Slight yellow No change.

:B Heagtl hrs Pale ye1low Slight yellow. As is shown in Table V both Pickup and Work Index 5hrs 151% cha g N changeincrease with an increase in concentration of reactants. 3%; 52 slightownow Table VI, below, shows the resistance of the treated 0 Agirg N h a N h materi l to bacteria, It is evident from the data in 1 mos o0 0c ange' Table VI that the treated material has greater bacterial resistance than the untreated material. Table VII shows the unique freedom from color forma- Th oil bu l tests were Carried Out y burying Stripsv tion achieved with the process and product of the inof treated and untreated wool fabric in a standard soil. ventiom I may b l d d from th t bl th t ro- The Strips used were about 0116 inch across. and about 8 Ieinaceous material treated with the process of the into 10 inches long- The Standard Soil Was P p and vention has color stability equal to or better than that the test was run according to ASTM D 684-45T Test 7 of th pi-oteinaeeous t i l it lf, for Resistance of Textile Materials to Microorganisms. I Order more l l t di l th nature of th The water content of the soil was adjusted to 30%. The present i ti ifi examples f th ti f Soil Was Placed in an Oven Where the t6II1P61att1f Was 25 the invention are hereinafter given. It should be unmaintained at C. The tensile strength of the samd t d, h h t thi i d l l b way of P was recorded, and y Were then buried in the S011- example and is intended neither to delineate the scope After the Samples had been immersed for varying periods of the invention n01 limit the ambit of the appended of one week, two weeks, or three weeks, samples were l l i removed and tensile strength again recorded. The data 30 I the examples the term parts refers to parts by shown in Table V1 is the percent tensile strength retained i ht, after burial. f 11 Example I The Bacillus subtilus test was carried out as o ows. The weight of the wool samples was determined and a i fi of 9 g .qf y; g 5 corresponding amount of prepared broth was weighed e compnsmg. S an m y 0 W00 an WhlCh had been fulled, 1n 80 parts of rsopropanol were out for each of the samples. The sterilized broth was dissolved 13 6 rt f h d th then inoculated with Bacillus subtilus bacteria as supplied Solution ad 2 Z 2 {1. by the American Type Culture Collection, of Washington, the Solution i dd S a m h DC. After inoculation the broth was allowed to stand the r S m e S 0 95 3 for two or three days to make sure that the inoculation 40 W0 u 2 3 were i i z f e hparts had been successful. Then, the tensile strength of sam n i1 2. en p i fi or our W 2, ple strips was determined and the strips added to the C 5 a W 1e mam ammgt F empera i at broth' the strips were allowed to remain in the broth 6 treated 9 papermaker S felt was used i warm water and dried. The felt was found to have infor the predetermined time shown in Table VI. The creased in Wei b 7 Th d t broth was maintained in the bacterial oven as in the extend individuil t e fi B g 3 previous soil burial tests at 30 C. during this time. The b a mximat 1 g y percen d g g strips were removed from the broth, sterilized and their g gf f g requlre t 3 tensile strength determined. The final tensile strength The roduct g th y i' was then compared to the tensile strength before the f It O at WOO en paperexposure to the Bacillus subtilus. ma ers e an 1 not lsco or urmg TABLE VI Example II The procedure of Example I was repeated except that Percent Tensile strength Retained the diphenolic acid was dissolved in 1600 parts of Water Time at 96 C., no isopropanol being used. The water was Untreated Treated then cooled to 74 C., and treatment of the fabric was carried out as in Example I. A weight increase of 6.8% so Burial Test: resulted. The average force to extend a fiber by twenty wigg percent was increased by 91.9%. The ultimate tensile 3WkS 0 19 Strength of the treated fabric was of that of the a g Test! original fabric. The product was the color of the natural ys 15 92 21 days 15 75 fabrlc and did not dlscolor during use.

Table VII, below, shows the color of the treated ma- Example terial to be as stable as the untreated material upon 5 A stock dyed woolen blanket fabric, weighing 60 aging and when exposed to light and heat. pounds was treated in a piece dye kettle with a solution The stability of color to ultraviolet light was determade up of 13.75 pounds of diphenolic acid, 8 pounds mined by exposing an untreated woolen sample and a of 37% formaldehyde solution, and 12.5 gallons of methatreated woolen sample about an inch wide by 8 inches nol in gallons of water. The treatment was conlong to an ultraviolet lamp at a distance of about one 7 tinned for one hour at F. The treated blanket foot. The results are shown in Table VII. was rinsed with warm water, napped and dried. After The stability of color to heat was determined by plactreatment and drying the weight was found to have ining treated and untreated Woolen samples in an oven creased by 8%. The product was the color of the original at a temperature of 100 C. The effect on color at fabric and did not discolor during use. predetermined intervals is shown in Table VII. 75 The treated blanket was then washed in a'home type automatic washer; an untreated blanket was washed under the same conditions as a control standard. The size changes (shrinkage) obtained with the two blankets were as follows:

A solution of isopropanol in water was prepared in which the isopropanol was equal to of the solution volume. The total volume used was 800 cc. This was equivalent to a 16:1 liquor to wool ratio.

Next, 0.03 M diphenolic acid and 0.06 M benzaldehyde were added to the solution. A wool sample of 50 g. was immersed in the solution for one hour at 74 C. The wool sample was then rinsed and dried. The product wool was examined and found to be colorless. The product did not discolor during use.

Example V The procedure of Example IV was repeated except that acetaldehyde was substituted for the benzaldehyde. Upon examination, the color of the wool was found to be unchanged by the treatment; the color did not change during use. The Percent Pickup was found to be 6.4. The Work Index was 102.4, and the Pounds Tensile was 117.5 as compared with the Standard of 120.

Example VI The procedure of Example IV was repeated, except that propionaldehyde was substituted for the benzaldehyde. Upon examination of the product, the color of the original wool was found to be unchanged. The color did not change during use. The Percent Pickup was 6.0%. The Work Index was 101.1, and the Pounds Tensile was 126.4 against a Standard of 120.

Example VII The treatment of a woven fabric containing 55% wool and 45% nylon was carried out as follows. In 80 parts of isopropanol were dissolved 13.6 parts of diphenolic acid. The solution was added to 1520 parts of water at 60 C. To this solution were added 2.9 parts of formaldehyde. Into the resulting solution were immersed 100 parts of the woven fabric containing 55% wool and 45% nylon. Treatment was carried out for one hour at 60 C. The fabric was then rinsed with warm water and dried. The fabric was found to have a dry weight increase of 8.4%.

Example VIII The procedure of Example VII was repeated except that 100 parts of a woven fabric containing 50% wool, 25% nylon and 25 Dacron, a polyester resin, were used. The dry weight increase after treatment was found to be 7.1%.

Example IX The procedure of Example VII was repeated except that 100 parts of woven fabric containing 55% wool and 45 Dacron, a polyester resin, were used. The dry weight increase after treatment was found to be 5.0%.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. A process for treating keratin fibers comprising immersing keratin fibers in an aqueous solution of 4,4-bis- (4-hydroxy phenyl) pentanoic acid and an aldehyde selected from the class consisting of formaldehyde, acetaldehyde, benzaldehyde and propionaldehyde, and drying said keratin fibers, whereby the chemical and physical properties of the keratin fibers are improved without changing the color of said fibers.

2. A process for treating keratin fibers comprising immersing keratin fibers in an aqueous solution of 4,4-bis (4- hydroxy phenyl) pentanoic acid and formaldehyde, and drying said keratin fibers, whereby the chemical and physical properties of the keratin fibers are improved without changing the color of said fibers.

3. A process as defined in claim 2 wherein acetaldehyde is substituted for said formaldehyde.

4. A process as defined in claim 2 wherein benzaldehyde is substituted for said formaldehyde.

5. A process as defined in claim 2 wherein propionaldehyde is substituted for said formaldehyde.

6. A process for treating keratin fibers comprising dissolving 4,4-bis(4-hydroxy phenyl) pentanoic acid in water heated to at least about C., adding formaldehyde in a ration to said acid of between about 1:2 to 4: l, immersing the keratin fibers to be treated in the solution, and drying said keratin fibers, whereby the dimensional stability and bacterial resistance of said keratin fibers are increased without changing the color of said keratin fibers.

7. A process for treating keratin fibers comprising dissolving 4,4-bis(4-hydroxy phenyl) pentanoic acid and formaldehyde in an aqueous solution of alcohol, having a pH of between about 2 to 9, said formaldehyde being present in a ratio of 1:2 to 4:1 to said acid, heating said solution to between about 50 to C., immersing the keratin fibers in said solution for about one hour while maintaining said temperature, and drying said keratin fibers, whereby the dimensional stability and bacterial resistance are increased without changing the color of the keratin fibers.

8. A process for treating keratin fibers comprising dissolving 4,4-bis(4-hydroxy phenyl) pentanoic acid and formaldehyde in an aqueous solution of alcohol, having a pH of between about 5.5 to 6.5 and a molarity of about 0.02 to 0.08 based on said acid, said formaldehyde being present in a ratio of 2:1 to said acid, heating said solution to between about 60 to 100 C., immersing the keratin fibers in said solution for about one hour while maintaining said temperature, and drying said keratin fibers, whereby the dimensional stability and bacterial resistance are increased without changing the color of the keratin fibers.

9. A keratin fiber substrate modified with the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and an aldehyde selected from the class consisting of formaldehyde, acetaldehyde, benzaldehyde and propionaldehyde.

10. A keratin fiber substrate comprising at least about 25% by weight of keratin fibers modified with the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and an aldehyde selected from the class consisting of formaldehyde, acetaldehyde, benzaldehyde and propionaldehyde.

11. A keratin fiber substrate modified with the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and formaldehyde.

'12. A keratin fiber substrate modified with the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and acetaldehyde.

13. A keratin fiber substrate modified with the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and benzaldehyde.

14. A keratin fiber substrate modified With the reaction product of 4,4-bis(4-hydr0xy phenyl) pentanoic acid and propionaldehyde.

15. A papermakers felt comprising a woven wool fiber base modified With the reaction product of 4,4-bis(4-hy droxy phenyl) pentanoic acid and formaldehyde.

16. A woven fabric containing at least about 25% by Weight of wool and the remainder of synthetic fibers, modified With the reaction product of 4,4-bis(4-hydroxy phenyl) pentanoic acid and formaldehyde.

17. A keratin fiber material modified with up to about 20% by Weight of the reaction product of 4,4-bis(4-hydroxy 'phenyl) pentanoic acid and formaldehyde.

References Cited by the Examiner UNITED STATES PATENTS 1,539,517 5/1925 Schmidt 894.24

2,512,709 6/ 1950 Bea-chell 892.24 X 2,676,170 4/1954 Patterson 8-94.24 X

2,837,563 6/1958 Alles 8-94.24 X

2,907,738 10/ 1959 Greenlees.

FOREIGN PATENTS 648,854 1/1951 I Great Britain.

OTHER REFERENCES Lynn: Advances in Textile Processing, vol. 1, 1961, pages 245249, pub. by Textile Book Publishers Inc., 1961, New York.;

NORMAN G. TORCHIN, Primary Examiner. 

1. A PROCESS FOR TREATING KERATIN FIBERS COMPRISING IMMERSING KERATIN FIBERS IN AN AQUEOUS SOLUTION OF 4, 4-BIS(4-HYDROXY PHENYL) PENTANOIC ACID AND AN ALDEHYDE SELECTED FROM THE CLASS CONSISTING OF FORMALDEHYDE, ACETALDEHYDE, BENZALDEHYDE AND PROPIONALDEHYDE, AND DRYING SAID KERATIN FIBERS, WHEREBY THE CHEMICAL AND PHYSICAL PROPERTIES OF THE KERATIN FIBERS ARE IMPROVED WITHOUT CHANGING THE COLOR OF SAID FIBERS. 